Carotenoids are lipids, i.e. fat soluble yellow to orange to red pigments, universally found in the photosynthetic tissue of higher plants, algae and photosynthetic bacteria. They are found spasmodically distributed in flowers, fruits, roots of higher plants and fungi and bacteria. Carotenoids are synthesized de novo in plants and can be found in animals, especially marine invertebrates tending to concentrate in the gonads, skin and feathers. All carotenoids found in animals are ultimately derived from plants or protistan (unicellular or acellular organisms) carotenoids, although interestingly enough, because of metabolic alteration of the carotenoids (pigments), some carotenoids found in animals are not present in plants or protista.
Carotenoids are tetraterpenoids, consisting of eight (8) isoprenoid residues and can be regarded as being synthesized by the tail to tail dimerization of two (2) 20 carbon units each themselves produced by head to tail condensation of four (4) isoprenoid units. Hydrocarbon carotenoids are termed carotenes and oxygenated carotenoids are known as xanthophylls. Beta-carotene (β, β-Carotene) is probably the best known of the carotenoids. However, other carotenoids may include, but are not limited to, lycopene (ψ, ψ-Carotene, C40H56), lutein or xanthophylls (β, ε-Carotene-3,3′-diol, C40H56O2) and zeaxanthin (β, β-Carotene-3,3′-diol, C40H56O2).
Other processes for extracting carotenoids from certain sources have been proposed. However, each has certain disadvantages and limitations. The most notable and common disadvantage of all prior art processes is the limited amount of carotenoids extracted from the source with respect to the total amount of carotenoids presenting the source, i.e. low yield and concentrations. Another major disadvantage in the instability of the extracted carotenoids which are susceptible to oxidation which further decreases their yield.
One prior art process describes a process for the formation, isolation and purification of comestible xanthophylls crystals from plants, namely lutein from marigold flower petals, zeaxanthin from wolf berries or capsanthin and capsorubin from red pepper. Such plant sources contain the xanthophylls in the esterified form as a mono- or di-C12–C18 long chain fatty acids such as lansic, myristic oleic, linolanic and palmitis acids, i.e. in the natural oils of the plant source.
This prior art process extracts the natural oils from the plant with hydrocarbon solvents, which are know to be toxic. This step includes repeated soaking of dried and ground marigold petals with warmed hexane for at least 8–10 hours. Next, the solvent must be removed so that only the natural oils containing the xanthophylls esters, i.e. oleoresin, remains.
The oleoresin is saponified by admixture with propylene glycol (1.2-propanediol) and an aqueous alkaline solution, preferably potassium hydrodroxide. The soaps generated by this saponification process attach to some of the carotenoids in the oleoresin as the mixture is heated under closely monitored temperatures for a considerable amount of time.
The saponification reaction cleaves the fatty acids, i.e. natural oils, from the xanthophylls diester, producing free xanthophylls in the form of crystals, as well as potassium soaps or sodium soaps of the fatty acids. Finally, the crystals are filtered and washed. The amount of xanthophylls extracted is approximately 6% by weight with approximately 80% natural oils.
Another prior art process describes methods to remove the natural oils in order to extract the carotenoids. This process attempts to extract hydrophobic compounds by admixing non-polar solvents, water-soluble organic solvents and a fruit or vegetable source for approximately 15–60 minutes. After admixing, the mass is forcibly centrifuged at 5000 rpm to draw of the supernatant for drying and further techniques to extract the carotenoid content. Again, the concentration and yield of the extracted carotenoids is quite low.
Still another prior art process describes the use of calcium analogs of various types to precipitate the carotenoids from the liquid phase of a slurry of all the components of the fruit or vegetable bring processed. Initially, a fruit or vegetable slurry is separated into a liquid fraction and a pulp fraction. Next, calcium analogs are added to precipitate the carotenoid from the liquid fraction. After precipitation, the carotenoid-enriched solids are separated from the carotenoid-depleted liquid fraction. The carotenoid-enriched solids may be utilized directly or may be further purified in order to separate the carotenoids from the other precipitated constituents. Further purification may include chemical and enzymatic hydrolysis and chemical and enzymatic degradation. As discussed above, the concentration and yield of the carotenoids are quite low and the carotenoid is present in a considerable amount of natural oil.
One disadvantage of the above methods is the low concentration and yield extraction levels for carotenoids from natural source. Another disadvantage is that the prior art processes have not been able to adequately dissociate the carotenoid from suspension in natural oils. Other disadvantages of these processes include time consuming and expensive steps necessary to generate an intermediate carotenoid-containing substance which each must be further manipulated in order to obtain a useful form of carotenoids. Accordingly, all known prior art processes are extremely time-consuming, ineffective, inefficient, costly to operate, involve multiple steps and cannot produce a near-pure carotenoid extraction in marketable quantities and concentrations.
Therefore, there exists a need in the art for a process which efficiently and effectively extracts high concentration and yield levels of biologically active, near-pure carotenoids in a stable form from fruit or vegetable sources, such as, but not limited to: 1) solids obtained from the waste treatment of the suspended solids present in the waste water from fruit or vegetable processing plants, 2) the pumice, or rough cut grinding of the exterior of the fruit or vegetable prior to processing of the fruit or vegetable, 3) fines and or slices of the fruit or vegetable present as a waste or as a disclaimed product, 4) any and all solids present from floor sweeping or general maintenance of the fruit or vegetable processing facility. There is also a need for such a simple, inexpensive, high-volume and manageable process that quickly penetrates the fruit or vegetable sources to extract higher yields of carotenoids that previously thought available all in a stable, transportable and useable form.